Children of long-lived parents have a lower mortality risk than their spouses, with whom they share environmental conditions. Furthermore, siblings of centenarians have a greater chance of becoming centenarians themselves, compared to age-matched controls. Thus, while environmental factors play an important part in aging, evidence suggests lifespan is at least under moderate genetic control. Since the early 1980s, scientists have known that mutations of single genes can extend lifespan in animal models. The work since has led to the discovery of several genes, signaling pathways, and cellular processes important for aging. For example, increased cellular metabolism associated with proliferation is known to increase the formation of reactive oxygen species (ROS), DNA damage, and replicative stress, all of which are theoretical contributors to aging. We have preliminary data to suggest that MTBP, a protein that we have recently shown is important in regulating cancer development, is also a novel regulator of proliferation and aging. We hypothesize that MTBP modulates the deleterious effects of proliferation and cellular metabolism that contribute to aging. To test this hypothesis, we propose three aims that use both in vitro and in vivo approaches. In the first aim, we plan to characterize novel protein interactions involving MTBP. In the second aim, we will examine the effect of MTBP on cellular processes implicated in aging. In the third aim, we will evaluate the role of MTBP in mammalian aging, in vivo, by using a mouse model. The results from the proposed study will further our understanding of the biological processes that govern aging and the role of MTBP in these processes. Our work is likely to identify a novel therapeutic target to retard aging, promote healthy aging, and treat and/or prevent age-related diseases. The didactic MD/PhD training plan at Vanderbilt University School of Medicine provides a supportive environment that will allow me to meet the goals of this research proposal and gain the training necessary to achieve my career goals in science and medicine. During my training, I will learn to think critically, engage others in scientific discourse, and innovatively question the unknown. Outstanding courses, seminars, and career development activities are provided at Vanderbilt to support trainees. My sponsor, Dr. Eischen, will also provide valuable training and critical one-on-one mentorship to ensure success in graduate school and beyond. Completing this training plan will help me meet my career goal of becoming a productive physician-scientist, who cares for patients and conducts biomedical research that furthers our understanding of human disease and aging.